3.2 Noise Levels

[Guest]

Last week I was at Castle Combe for a track day - a noisy day with a 105db limit.

My 3.2 has a 100% standard exhaust - a little old but standard nonetheless. Colour me surprised when the noise tester says 107db, sorry, no track day for you! Well not entirely surprised as my own noise testing (with Essential Simon' s kindly lent noisemeter) led me to believe that I was close to 105db anyway. Well after a little pleading and disbelief and saying " but its a dead standard!" they retested and I guess, fudged it and said it was 104.5db.

Well, kind of predictably, I thought that I would need some new mufflers or something for future track days. I have been seeking advice all over and here is what I have found. The noise testing reg.s (at Combe anyway) require that the test is taken from the driver' s side. So my test there was incorrect - as were my tests at home. Advice came from JAZ and they said that they have had this battle with the noise testers before, in the context of the race cars they prepare. They have driven my car and believe that there is no way it would fail any noise test (other than maybe a 98db test).

So maybe, the moral is to question the procedure on any noise test - if you fail it. It has been very difficult to get any hard info on noise tests, but, if you have a standard 3.2, it is safe to say that you should be fine at any PCGB event.

Richard

 

[Guest]

What we really want to know is how was the track day!

I am at castle combe later in the year, I hear it is quite a tight circuit (in that it has few large run off areas) is that about right?

 

[Guest]

Some Noise Testers can be frustrated if they ' Fail to Fail' someone. The MSA Blue Book requires the meter to ' be situated 1m from the exhaust outlet and at 45 degrees from the direction of exit. If this is not carried out correctly then perhaps a gentle reminder.

Having said that I still don' t understand what it measures! I sprinted a Seven with a Wunoff custom stainless steel silencer. Glorious sound but a bit wearing on the way to Le Mans! Used to come out at 105db (this was a manufacturers guarantee) My mate drove a 5.3 V12 Cobra. Glorious sound, even the commentators used to draw peoples attention too it. Noisy? 112db (sometimes money changed hands!) But anyone who has ever had the dubious pleasure of being near a bike engined car will know it is like a dentists drill (surprisingly quite unlike it sounds in a bike!) BUT these things always seem to record about 98db.

Confused? I' ll get me white coat!

 

[Guest]

What we really want to know is how was the track day!

I am at castle combe later in the year, I hear it is quite a tight circuit (in that it has few large run off areas) is that about right?

The track day was good. The run-off areas were not as tight as I was lead to believe, but it is overall a fairly fast track. Coming on to the front straight, there is a wall that is quite close, but it is difficult to commit yourself at sufficient speed for this to be a problem ie., sufficient speed on entry to run really wide out past the kerbs and into the wall. Most took it in 3rd and accelerated thru the corner - which was pretty safe because you are on the power all the way thru the corner. I think you could work up to taking it in 4th (heard of a couple of people doing this) if lap times were the ultimate goal but the risk then is that you may need a midcorner lift.

Also at the back of the circuit you brake (slightly downhill) heading straight for a wall before turning right. No problems unless catastrophic brake failure but your inclination was to brake early. I usually did a tiny left foot brake just before the braking zone to check that the pedal was still there.

The chicanes are fun - the second one in particular, which comes up very quickly after the preceeding corner. Easy to out brake yourself there. A dip in the apex of the second chicane allows you to unsettle the rear and drive thru a nice second gear oversteer slide if you get it just right.

Biggest concern were the bumps on the front " straight" . Because this straight is more of a curve it is not so easy to brake on the straight. I found that one bump was right where I wanted to brake. I was just on the limiter in 4th and the bump made it tricky to get the old foot on the brake pedal - I nearly missed the pedal altogether a couple of times. So I started braking a little early - its a track day after all.

Top tip is to take a good hard look at the circuit map on the wall in the main restaurant building (where the breifing is) as " the line" is marked on the map. Try to memorise it and check up on your progress between sessions - it will help wit the front straight bit and the next corner.

R